I have a 1953 Chevy truck. It has the original 216 engine and Rochester Carb. After it has been sitting over night or for long periods of time I am having problems starting it. Even with the choke fully out it has a hard time catching. If I take of the air filter and have my fiance cup her hand over the carburetor to restrict airflow it will start right up. My fiance is not happy about smelling like gas every time we need to use the truck. Any advice as to what the problem is and how I can fix it?